Tacrine



Better Known as: Cognex

 * Marketed By: Parke Davis Pharmaceuticals


 * Major Indication: Alzheimer's Disease


 * Drug Class: Acetylcholinesterase Inhibitor
 * Date of FDA Approval (Patent Expiration): 1993 (N/A)


 * 1994 Sales: $100 Million
 * Importance: One of the the first treatments for the symptoms of Alzheimer's Disease, although no definitive proof exists as to whether it alters the progression of the disease.
 * See: Pharmaceutical Drugs for more information about other drugs and disorders

Mechanism of Action
Tacrine is an Acetylcholinesterase (AChE) inhibitor. It binds to the active site of AChE, utilizing many of the same residues which bind and break down acetylcholine. By inhibiting AChE, the important neurotransmitter, acetylcholine, is degraded at a slower rate, helping reverse the marked decrease in neuronal function evident in Alzheimer's Disease patients. Tacrine primarily interacts with residues Phe 330, His 440, Trp 84, & Ser 200 in tightly binding to the AChE binding site via pi stacking interactions. It is clearly visible how Tacrine interferes with the binding of acetylcholine, outcompeting acetylcholine for nearly the same space in the active site.